1. Field of the Invention
The disclosure relates to a vehicle-door opening and closing device, and more particularly relates to a control device for a power unit of a vehicle-door opening and closing device.
2. Description of the Related Art
A conventionally well-known power unit includes a power close mechanism that turns a latch of a latch unit to displace a vehicle door from a half latched state to a fully latched state, and a power release mechanism that releases the fully latched state to bring the vehicle door to an openable state (for example, see Japanese Patent Application Laid-open No. 2016-017361, Japanese Patent Application Laid-open No. 2014-009477, Japanese Patent Application Laid-open No. 2016-017347, and Japanese Patent Application Laid-open No. 2014-152496).
In control of the power unit, signals from a plurality of switches are used, which are roughly divided into a driven-side switch group for detecting states (positions) of the latch and a ratchet of the latch unit and a driving-side switch group for detecting states (positions) of drive mechanisms that turn the latch and the ratchet with motor power. In addition to the signals from these switches, detection of a load current of the motor is also used in the control. The load current of the motor is an excess current occurring when a drive member driven by the motor abuts on a mechanically immobile member and stops driving.
Detection of the load current of the motor is used as a signal when a drive gear is to be returned to a neutral position after the power unit is actuated. However, because a voltage used in an automobile is low, a detected excess current has a quite high value. Therefore, if a circuit is designed according to the quite-high excess current, a fuse with a quite large capacity and a tough substrate are required, which is quite disadvantageous in the cost.